1. Technical Field
The present invention relates to a switch device that outputs an ON or OFF signal at a predetermined operating position on the basis of an analog output from an electrical component, and more particularly, to a switch device having a click mechanism.
2. Related Art
As a switch device, there is a type that outputs an ON or OFF switching signal by contact and separation between a movable contact point and a fixed contact point, and a type that outputs an ON or OFF switching signal when an analog output exceeds a predetermined threshold value. Such a switch device has a click mechanism for generating a click feeling when an operating unit is at a predetermined position.
When the switch device is used as a switch device for opening and closing a power window, the switch device is disposed at an elbow support of a door in a vehicle, and an operating unit can be rocked in a pulling direction and a pushing direction from a neutral position. When the operating unit is operated in the pulling direction, the window is moved upward, that is, in a closing direction. When the operating unit is operated in the pushing direction, the window is moved downward, that is, in an opening direction.
The click mechanism of the switch device is configured to generate 2-step click feelings in the pulling direction and the pushing direction at the time of operating the operating unit. The switch device gives an instruction of a manual operation (window of vehicle goes up or down only during operation) at the first-step click position, and gives an instruction of an automatic operation (window continues to go up or down even after operation) at the second-step click position. To properly give an instruction, it is necessary to securely synchronize the time of the ON or OFF switching signal and the click position of the switch device.
In the switch device of a type that outputs an ON or OFF switching signal when an analog output exceeds a predetermined threshold value, there has been known a magnetic detection method using a permanent magnet rocked in association with the operating unit and a magnetoresistive element having electrical resistance varied with variation of magnetic field caused by movement of the permanent magnet. According to the magnetic detection method, it is possible to prevent decreases of reliability caused by the attachment of dust, or oxidation or wear of a contact point, as compared with the switch device of the type which contacts or separates a movable contact point and a fixed contact point.
In this case, the output from the magnetoresistive element is varied with the variation of the operation position of the operating unit. The output value is detected by a detecting unit. When the output value exceeds a predetermined threshold value, it is considered that the operating unit has operated by a predetermined degree and an ON signal is output. In addition, to notify an operator of the operation of the predetermined degree when the output value exceeds the predetermined threshold value, a click mechanism is provided to generate a click feeling at that position. However, the output voltage value from the magnetoresistive element varies by variations in temperature, and the relationship between the position of the operating unit and the output voltage value also varies when there is a deviation of completion of each switch device. In this case, the output time of the ON signal and the click position may deviate from each other. In such a case, the click mechanism provided to notify the operator of the ON position may result in confusion for the operator.
To solve the problem, it has been known that an output voltage value at the time of actually operating an operating unit at a click position is stored in a memory and the output voltage value is used as a threshold value. According to this method, it is possible to absorb differences of individual deviation. Such a switch device, for example, is described in Japanese Patent Application Laid-Open No. 2005-19100.
However, in the known switch device, an output voltage value that is a threshold value at the actual using time is not set. Accordingly, although it is possible to absorb the individual deviation, it is difficult to cope with variation in characteristic at the actual using time, that is, variation in relationship between the position of the operating unit and the output voltage value according to variation in temperature. For this reason, the position for detecting the position of the operating unit with the detecting unit and the click position in the operating unit may deviate from each other, and it may be difficult to synchronize the time when the switch device outputs a signal and the time when a click event occurs.